Interpretive Summary: Teosinte is maize’s wild relative, and it harbors tremendous genetic diversity. While much of this genetic variation was captured by maize, there are numerous traits and genetic variants that are only present in teosinte. Many of this variation could be useful for maize improvement. Genetic variants controlling ear morphology and kernel quality were identified. Further evaluations will be required to determine if these would be useful improvements to the maize germplasm pool.

Technical Abstract:
Our previous association analyses showed that variation at major regulatory genes contributes to standing variation for complex traits in Balsas teosinte, the progenitor of maize. This study expands our previous association mapping effort in teosinte by testing 123 markers in 52 candidate genes for association with 31 traits in a population of 817 individuals. Thirty-three significant associations for markers from 15 candidate genes and 10 traits survive correction for multiple testing. Our analyses suggest several new putative causative relationships between specific genes and trait variation in teosinte. For example, two ramosa genes (ra1 and ra2) associate with ear structure, and the MADS box gene, zagl1, associates with ear shattering. Since zagl1 was previously shown to be a target of selection during maize domestication, we suggest that this gene was under selection for its effect on the loss of ear shattering, a key domestication trait. All observed effects were relatively small in terms of the percent of phenotypic variation explained (< 10%). We also detected several epistatic interactions between markers in the same gene that associate with the same trait. Candidate-gene-based association mapping appears to be a promising method for investigating the inheritance of complex traits in teosinte.